Anamorphic prism systems are known to compress or expand light beams, but they have not been used for image capture for a variety of reasons. These prism systems are afocal and do not focus an image onto an image plane, making them unsuitable as an imaging system. Typically, anamorphic prism systems are designed for collimated light from one incident angle and therefore their performance degrades with off axis light, resulting in a lens with a very limited field of view. Many anamorphic prisms have chromatic dispersion resulting in chromatic aberrations making them unsuitable for multi-color images. Accordingly, anamorphic prism systems are almost exclusively used to shape laser beams, often monochromatic, and are generally referred to as beam expanders and beam compressors.
Achromatic anamorphic prism systems, generally require multiple prisms making them large and heavy. In addition, since the achromatic anamorphic prism systems only compress or expand in one dimension, it would require multiple of these systems to compress equally in two dimensions to maintain the image aspect ratio, which makes the systems even larger and heavier. For these reasons anamorphic prism systems have not been used for image capture.
Imaging devices such as cameras, microscopes and telescopes can be heavy and large. A large portion of this weight is due to the design of the optical lens elements, which can include heavy curved lenses, and the structure to support these lens separated by long focal distances.
These imaging devices can be large (thick) mainly because in a typical lens system, the opening aperture to system device depth ratio is small. Moreover, to optically improve image resolution with the traditional lens systems, more device depth (longer focal length) is required in order to reduce lens refraction and minimize lens aberrations. The device depth of the imaging device can limit the imaging systems performance and design. For example, the size and weight constraints of mobile, compact, or weight constrained imaging devices can limit resolution because they constrain the maximum focal length. The disclosed invention can increase the effective focal length in these systems, and improve resolution with the same size and weight constraints.
Additionally, conventional curved lenses have many different types of aberrations that reduce image resolution (spherical, coma, chromatic, and others). To correct these aberrations, conventional curved lenses use extra large pieces of precision glass, adding weight, size and cost to the lens system. The disclosed invention can reduce the size, weight and resulting cost of conventional curved lenses, and in some devices eliminate their use entirely.